The formation of a War Cabinet was planned and recorded in the War Book during the 1930's. Its formation was announced on 15 September 1939 and it met for the first time on 27 September 1939.  It comprised the Prime Minister and Treasurer (then R G Menzies), the Attorney-General, the Ministers for Supply and Development, Defence, External Affairs and Information, and Commerce, Mr F G (later Sir Frederick) Shedden, the head of the Department of Defence was appointed Secretary and attended all meetings.  In June 1941, following the British practice, the War Cabinet agreed that one of Shedden's subordinates should also be admitted to its meetings and that other Ministers, the Chiefs of Staff, other experts and representatives of the Allied Governments should be invited as required.  [See CRS A2690, Minute Secretary's (H L Port) Handwritten Notes on Meetings of the War Cabinet and Advisory War Council, 1941 (June 10 - December 31).]
 
On 11 December 1941 by Minute No 1570 (see CRS A2673), the War Cabinet approved certain rules and procedure governing both War Cabinet and Advisory War Council business. To avoid duplication between both bodies, it was decided that:
 "(i) the following will be dealt with at the Advisory War Council
      only:
        Reviews of the international situation
        Strategical Appreciations
        Reports of Operations
        Progress Reports
        Major questions of Policy as determined by the Prime Minister
 (ii) where decision by the War Cabinet as the Executive are
      necessary,the assent of Ministers at the Advisory War Council
      will be taken as confirmatory approval of the Advisory War
      Council recommendation. The Secretary to the War Council, as
      Secretary to the War Cabinet, will prepare War Cabinet
      approvals in such cases as well as Advisory War Council minutes
      and they will be signed by him and submitted to the Prime
      Minister for approval and notification to Departments."
 
(This form of delegation was of some significance until the middle of 1943, when the Advisory War Council began to decline in importance.)  
It was also established that the War Cabinet business fell into two main divisions:
  (i) Major and general questions which are of equal concern to all
      Ministers; and
 (ii) Other questions of a more specialised nature concerning       
      particularly Departments and groups of Departments.
 
The procedures to be followed were then laid down.
 
War Cabinet Minute No 4626 of 19 January 1946 (See CRS A2673) approved the abolition of the War Cabinet and the reconstitution of the Council of Defence.
 

Sources
 
War Cabinet Minutes Nos 1570, 11 December 1941 and 4626, 19 January 1946.  Australian Archives: CRS A2673
 
Federal Directory, 1943, p 17
 
S Encel, Cabinet Government in Australia, MUP, 1962, p 106, p 108, 
p 338
 

Historical agency address
  1939-1941: Victoria Barracks, Melbourne Vic
by1941-1946: Canberra ACT